WO1994018301A1

WO1994018301A1 - Cleaning composition

Info

Publication number: WO1994018301A1
Application number: PCT/GB1994/000242
Authority: WO
Inventors: Paul Brougham
Original assignee: Laporte E.S.D. Limited
Priority date: 1993-02-12
Filing date: 1994-02-09
Publication date: 1994-08-18
Also published as: GB9302855D0

Abstract

A highly viscous, highly alkaline caustic cleaner containing sodium hydroxide, a bulking agent and polyacrylic acid dispersing agents contains at least 40 % total solids by weight. The composition may be used in the cleaning of vessels used in the food, dairy and beverage industries. The composition is of particular use in the cleaning of food fryers.

Description

CLEANING COMPOSITION

The present invention relates to the use of a highly viscous and highly alkaline aqueous composition comprising sodium hydroxide for use in cleansing heat affected metal surfaces. Large metallic vessels are used throughout the food, dairy and beverage industries. Many of these vessels are used in processes involving heat, such as plate heat exchangers, scraped surface heat exchangers, evaporators and fat fryers. There is a tendency for a build-up of residual solids upon the vessel surfaces. These solids must be periodically removed in order to ensure that the vessels meet the high hygiene levels required in the relevant industry.

A number of compositions have been used in cleaning such vessels. Liquid cleaners are usually highly aqueous and therefore often do not have a sufficiently high concentration to attack the solid build-up. Powder cleaners can be added but, as these are often highly alkaline, there are health and safety requirements which must be observed. Furthermore, no satisfactory powder dosing system has been placed on the market.

High viscosity, high alkaline cleaning compositions have been disclosed in the art. US-4521332 (Milora) discloses only alkaline aqueous cleaning dispersions comprising sodium hydroxide, a bulking agent such as sodium carbonate and polyacrylic acid dispersing agents. The compositions contain at least 40% total solids by weight and resist separation into substituent components.

WO 88/05814 (Pennwalt Corporation) discloses highly viscous, highly alkaline caustic cleaners containing from 40 - 80 wt. % total solids having 5 - 30 wt. % inorganic particulate materials dispersed therein, such as alkaline silicates, which are non-reactive and insoluble in the caustic composition. The solids are useful for their detergency, soil-suspension and surface-active properties.

The compositions described above have been previously used in the cleaning of metals, particularly steel, prior to working. There is particular description of the use of such materials in the cleaning of steel strips after the said strips leave the rolling mills prior to annealing or coating. As far as the present Applicants are aware, there is no disclosure of the use of such compositions in the cleaning of metal vessels previously described as used in the food, dairy and beverage industries. The ability of new materials to clean the vessels is particularly surprising in view of the high level of solid build-up which may occur during, e.g. cooking processes. The Applicants have also discovered that the highly viscous preparations can be more easily dosed into the vessels to be cleaned. The compositions do not induce a high exothermic reaction when dissolved in water. Such exothermic reactions may be unacceptably violent if cleaners of the prior art, such as powders, are added to hot water.

According to the present invention, there is disclosed the use of a highly alkaline cleaning composition in the removal of soil material from vessels used in the food, dairy and beverage industries. The compositions comprise at least 40% solids by weight and resist separation into individual components.

The compositions used in the process according to the present invention will preferably comprise, as percentages by weight: Sodium hydroxide : 10 - 45%

Alkali metal or ammonium salt of polyacrylic acid : sufficient to gel composition

Builder 0 - 10 % Surfactant 0 - 10 %

Chelator 0 - 10 %

Bulking agent 0 - 10 %

Water to 100 %

SUBSTITUTE SHEET Further reference is made to US-4521332 for further examples of compositions which are suitable for use in the process of the present invention.

The compositions may be diluted to a concentration of from 0.05 to 10% by weight with water.

Cleaning may be carried out by raising the solution to a temperature within the vessel to be cleaned of from 50° to 100°C. After cleaning, the vessel is rinsed with fresh water.

The following example describes a process according to the present invention.

Examples:

An industrial fat fryer which had been used in the preparation of fried foodstuffs was drained of the cooking oil. Water was flushed through the system. A 2% solution of the following composition was prepared with water at room temperature.

Ingredient Wt.

Caustic Soda Liquor (47%) 89 . . 63 Soft Water 3 . . 62 Sodium Hexametaphosphate 2 . . 00 Sodium Gluconate 0. . 50 Tetrasodium EDTA Solution 0 . . 25 Narlex LD30 1 . . 00 Soda Ash (light) 2 . . 00 Triton CF76 (nonionic) 1. . 00

100. , 00

The fryer was heated to 93°C. The cleaning composition was circulated for two hours within the fryer system. The system was then cooled to room temperature and the cleaning composition drained. The fryer was again flushed with water. The fryer did not show any visible soil.

In a second cleaning test a 1.5% solution of the composition was used and raised to the boil. The solution was held at that temperature for 30 minutes. During this time, carbonised food residues were removed from the base, sides and conveyor of the fryer and floated to the top of the cleaning solution. After holding the solution at the boil, the solution was discharged and the fryer filled with fresh water. This was then brought to the boil and immediately discharged.

Inspection showed the inside of the fryer to be clean and free from carbonised residues. Loosened carbonised residues which had floated to the surface and adhered to the sides of the fryer at the liquid level were easily hosed away using fresh water.

SUBSTITUTE SHEET

Claims

1. The use of a liquid alkaline aqueous composition comprising at least 40% by weight solids, said solids including from 20-50 % by weight of sodium hydroxide, in a method of cleaning metal vessels used in the food, dairy and beverage industries.

2. The use as claimed in Claim 1 in the cleaning of food frying apparatus.

3. The use as claimed in Claim 1 or Claim 2 wherein the composition comprises from 10-45 wt % sodium hydroxide; alkaline metal or ammonium salt of polyacrylic acid in an amount sufficient to gel the composition, from 1-15 wt % of detergent builder; from 0.3-5 wt % of non-inionic surfactant, from 0.1-3 wt % chelator, from 0.5-20 wt % sodium or potassium carbonate.

4. The use as claimed in any one of Claims 1 to 3 wherein the liquid alkaline aqueous composition is diluted to a concentration of from 0.5 to 10 % by weight with water.

5. The use as claimed in any one of Claims 1 to 4 wherein the solution is charged to the vessel to be cleaned and heated to a temperature of from 50 to 100°C.

SUBSTITUTE SHEET